Many patients with chronic diseases or who are critically ill require frequent administration of fluids for nutritional or medicinal purposes. These medications are oftentimes delivered through an intravenous catheter such as a central venous catheter (CVC), peripherally inserted central catheter (PICC), and midline catheter, which provide vascular access and can be kept in place for durations lasting several days up to several months. Patients requiring dialysis, for example, may visit the healthcare setting for a few hours each week over a particular rotation, but outside of these dialysis sessions, the catheter is unused but remains indwelling to the patient for future visits.
Modern medical catheters that have a portion of the catheter body extending outside the patient (“percutaneous”) consist of an indwelling portion and an external portion that primarily acts as a conduit to the indwelling portion. Many catheters are multi-luminal, where each lumen may serve different functions depending on anatomic location and/or dictated clinical need. External to the patient, the multi-lumen catheter bifurcates into single lumen lines, where the distal ends of said lines consist of a standard medical fitting (e.g., luer) for connecting infusion lines or various medical equipment, and a clamp to prevent fluid movement and air embolism when the catheter is not being accessed. The site of bifurcation is often called the “hub” or “transition” and is traditionally a molded stock connecting the indwelling catheter to the external extension(s), residing immediately adjacent to the insertion site. The intravascular portion of the catheter usually is rich in antimicrobial technologies and has been optimized for fluid dynamic needs, but the hub and extensions, lying external to the patient, generally do not have as rigorous demands on biocompatibility and fluid dynamic function, acting primarily as a conduit for the passage of fluids.
Following placement of the intravascular catheter, it is often necessary to secure the catheter to the patient when used for extended periods of time to prevent axial displacement of the catheter with regards to its anatomical position. Securement of the catheter is generally accomplished by one of three means, which all involve the catheter hub: suturing the catheter hub to the patient's skin through eyelets in the wings extending from the molded hub; applying tape in a crisscross fashion over the catheter hub thereby securing the hub to the patient's skin; or placing the hub in a semi-flexible securement device which is held to the patient's skin by an adhesive base. The securement methods prevent axial movement of the catheter and resist snagging or tugging of external extensions with environmental articles.
Medical catheters are manufactured using polymeric compounds such as silicone, polyethylene, polyurethane, and polytetrafluoroethylene to increase biocompatibility and longevity of use. Despite precautions, catheter-related infections are a frequent and growing concern, having significant consequences to patient morbidity and mortality, and greatly taxing to healthcare resources. Infections stem from bacterial adsorption on the catheter surface, giving way to a prolific growth of a highly antibiotic-resistant community of cells called biofilm. The predominant sources of bacteria that colonize on intravascular catheters arise external to the patient, either through contamination of the intraluminal surface due to non-sterile catheter access (i.e., incomplete disinfection prior to line access) or along the extraluminal surface from microbial egress through the insertion site, facilitated by pistoning (back-and-forth movement of the catheter). Every time these central lines are handled pose a potential risk for contamination.
The long-hanging catheter extensions can cause abrasions to patient skin, are uncomfortable, and are particularly prone to contamination from the patient's daily activities. The extensions may become tangled in clothing or other articles that cause minute axial movement, where such movement can introduce pathogens at the skin surface through back-and-forth motions. In addition, the distal ends of the catheters, where caps and other barriers are attached, are easily dirtied, which can pose a risk to contaminating the sterile catheter lumen during clinical access. Moreover, such caps and barriers can be removed outside the clinical setting and reattached without proper cleaning; in such cases, bacteria colonize under the cap and are introduced to the entire intraluminal space and patient's bloodstream during the next clinical use. Furthermore, these extensions can sometimes break: inexpensive clamps are snapped, tubing becomes kinked, and so forth; and such event requires surgical intervention to replace the entire catheter.
Most protocols of prevention and treatment secondary to the imbued biocompatibility of the catheter involve daily cleaning of insertion site and locking the intraluminal space with potent antibiotics or anti-thrombogenic agents. In addition to the many antimicrobial coatings and novel characteristics to the catheter surface, all of these technologies address the complication of infection after contamination has already occurred, that is, by acting as a defense against a present contaminant.
It would therefore be advantageous to provide a self-sealing hub for use with a catheter that allows attachment and removal of various extensions, reduces the total surface area of the extravascular portion of the catheter for bacterial contamination, removes the portion that is most often the source of an infection's origin, facilitates better placement of insertion-site dressing, and removes the region prone to snagging, irritation, and other problems associated with dangling catheter extensions.